The present invention relates to geographic information system and, in particular, it concerns a system and method for dynamic distribution of location-related information between users with different perspective views, and for providing location-related information based on a wide-area geographical database.
The developing field of technology known as “augmented reality” relates to systems which supplement a view of the real world with additional visual information. This technology has potential applications in a wide range of contexts, for example, ranging from industrial production to tourist information systems and to games. Of particular relevance to the present invention is the context of information systems where a system provides a user with geographic information related to various objects or locations which he or she is viewing.
One example of an augmented reality information system is prototype system under development as part of a project entitled “Augmented Reality-based Cultural Heritage On-site Guide” or “ARCHEOGUIDE” funded under a European Union “Information Society Technologies” (IST) project. The system is intended to give users touring cultural heritage sites a three-dimensional display of reconstructed sites as an overlay to the directly observed ruined site. The system also provides audio-visual presentations related to objects being viewed by the user. Registration of the user's position and direction of regard are achieved by a two stage process including gross tracking by GPS and compass measurements followed by fine alignment by registration of images from a head-mounted camera with pre-calibrated images taken from different viewpoints around the site.
Although the Archeoguide system potentially offers a significant step towards a useful outdoor geographic information system, it suffers from a number of severe limitations. Firstly, the need to provide an extensive set of pre-calibrated reference images covering the site from many different viewing angles is very limiting. While such an approach may be feasible for highly localized applications such as cultural heritage sites, it cannot form a basis for vide area systems where the task of setting up a large number of pre-calibrated reference images giving full coverage of a large area from multiple viewpoints would quickly become prohibitive.
A further limitation of the Archeoguide system is the inability to convey updated or transient location-related information, or other dynamic information, between users. Since the information displayed is based on a predefined information databases, there is no convenient manner for two different users viewing the same region to relay location-related information to each other.
In the field of geographical surveys and cartography, there exist extensive geographical databases which store various geographical information tied to geostationary coordinates. Such databases may include a wide range of information regarding natural and manmade features such as hydro-topology (e.g., rivers, streams, underground water sources and aquifers), vegetation, manmade infrastructure (e.g. roads, electricity cables, water, gas and oil pipelines etc.), buildings and other geographical information. Such databases often also include information about the physical topography of the landscape in the form of a digital terrain model (DTM) and/or digital surface model (DSM), and aerial or satellite photographs, or “orthophotos”, which are tied to the geographic coordinate system at reference points. Such databases may provide partial or complete coverage extending over areas of many miles, for example extending over an entire urban area, natural park or other region of interest. In some cases, databases of this type encompass an entire state or country. Such databases have not previously been used as a basis for augmented reality applications or other information systems where information is presented in the context of video images or a direct view of the terrain.
There is therefore a need for a geographic information system which would allow distribution of location-related information between users with different perspective views. It would also be advantageous to provide a geographic information system which would operate on the basis of existing geographic information databases, thereby facilitating wide-area use of the system without extensive dedicated infrastructure.